This invention relates to the sprouting of various kinds of seeds and more particularly concerns an improved hydroponic method and apparatus for accelerated but not forced growth of seed sprouts in a novel atmosphere of mostly air and water droplets wherein circulation, humidity and temperature are easily controlled.
The sprouting of seeds for human and animal consumption is an art dating back several thousand years and probably having its origins in the Chinese culture. There are many types of seed sprouts which provide quick energy foods which are low in calories and provide substantial quantitites of protein, vitamins, minerals, amino acids and essential enzymes. Such seed sprouts are considered to be organically pure since it is not necessary that they be sprayed, dusted, dipped, or chemically treated or fertilized in any manner. Among the best known sprouts are those particularly deriving from the Chinese cuisine, these being beans such as mung beans, soy beans, etc. Among many other types of seeds which are inexpensive, nutritious, tasty, and easily sprouted are alfalfa, wheat corn, lentils, etc. Further suggestions of seeds which may be sprouted as well as methods for sprouting are found in THE COMPLETE SPROUTING COOKBOOK, by Karen Cross Whyte, published in 1973 by Troubador Press.
The art of hydroponics began in the mid 1930's, and it concerns the cultivation of plants in solutions without the use of soil. Methods differing in particulars have been developed but all heretofore known methods have two common features. First, plant nutrients are supplied in liquid solutions. Secondly, the plants are mechanically supported in some method, usually in some porous material such as peat, sand, gravel or glass wool which acts as a wick in relaying the nutrient solution to the roots of the plants. In other instances, particularly in known seed sprouters, the seeds are merely laid upon some type of simple porous support.
Several classifications of hydroponic culture methods are currently being used. The most practical one for commercial application is the sub-irrigation method in which plants are grown in gravel filled trays which are periodically flooded with nutrient solution. The solution is then allowed to drain after use and is then reused and may continue to be reused so long as sufficient nutrients remain in the solution. One major difficulty with this method is that the reused solution contains an unhealthy quantity of pollutants and other waste materials which are washed back onto the plants being grown. Thus, the opportunities for disease or rot are alarmingly high. Experience has shown the rotting or infection of but one or several seeds or plants soon spreads and ruins the entire crop. A second method is the so called water-culture method in which procelain jars are filled with solution and plants are placed in beds of glass wool or like material which are supported at the surface of the solution. The roots of the plants remain in the solution during growth. Again, the major problem with this method is the growing of plants in a stagnant solution wherein plant waste products and other pollutants are not carried away from the growing plants. Another method is the "slop" method in which quantities of solution are merely poured on the plant's support media in approximately equal amounts at regularly timed intervals. A variation on this theme is a dipping method in which the plant growth media is merely dipped into a nutrient solution at regularly timed intervals. A further refinement of these latter two practices is the so called drip method wherein a steady slow feed of nutrient solution is allowed to drip onto the growing plant media. In each of these cases, the nutrient solution is allowed to drain off of the growth media.
More recently developed hydroponic methods, particularly in the art of sprouting seeds, have included closed chambers having a sump, a water spray system, and a heating arrangement such as disclosed in U.S. Pat. No. 3,768,201 issued to Byong W. Yoo and in the Danish Pat. No. 80,265 issued to Michel F. Mahoudeau. A sprouter including a spiral aerator in a liquid supply in which seeds are soaked to be germinated is disclosed in U.S. Pat. No. 3,233,366. A similar system but one in which the seeds are suspended above the liquid and sprouted is disclosed in the Russian Pat. No. 234,040 issued to P. V. Danilchuk et al. A similar system is disclosed in U.S. Pat. No. 2,198,150 issued to G. E. Barnhardt. A major drawback in the invention disclosed in both of these latter two patents is that aeration is initiated at the base of a liquid supply whereafter moist air circulated about the seeds and roots being sprouted. However, waste products and other pollutants being deposited back into the liquid supply from the roots have no place to go but back to the aerator to be recirculated onto the plants thereby increasing the possibilities of rot and/or disease as discussed hereinbefore.
Of course, there are a number of additional United States and foreign patents which disclose one or more prior art features as discussed in various combinations. However, the ones most pertinent to the instant invention have been discussed above.
A number of problems have been observed with the use of known devices and methods for seed germination and sprouting in particular. Some of the known devices are rather complex and expensive and others require substantial periods of time of seed germination and sprout growth. A significant problem is that of bacterial or fungus growth caused principally by prevailing stagnant conditions as hereinbefore discussed. When just a few seeds (or in some cases only one seed) reach a stage of souring or rot, the entire crop may become quickly infected and soon completely spoiled. In general, the sprouting devices which are currently available operate in a manner which produces the deleterious condition of a stagnant environment, and this is principally due to a lack of air and water circulation. Where this problem has been recognized, such currently available sprouters include means for rinsing the seeds periodically in an attempt to deter bacterial growth that will otherwise occur. However, in such cases the waste product and pollutant laden solution is merely redistributed later back onto the sprouting plants; thus, the rinsing technique is no solution to the problem.